Semiconductive roller of an image-forming apparatus

Abstract

A semiconductive roller to stably generate high-quality images for a long period of time by efficiently inhibiting migration of free epichlorohydrin (ECH) component to a surface of the semiconductive roller includes an elastic layer formed of a semiconductive rubber composition including about 50 to about 70 parts by weight of a base rubber and about 30 to about 50 parts by weight of a hydrin rubber. An extracted amount of the ECH component from the elastic layer is about 2% by volume or less, wherein the extracted amount is determined based on a reduced amount of chlorine (Cl) intensity measured using X-ray fluorescence (XRF) analysis performed before and after extraction of the ECH component from the elastic layer using tetrahydrofuran (THF).

What is claimed is: 
     
       1. A semiconductive roller, comprising:
 an elastic layer formed of a semiconductive rubber composition including:
 about 50 to about 70 parts by weight of a base rubber; and 
 about 30 to about 50 parts by weight of a hydrin rubber as a copolymer inhibiting forming of migration pathways of free epichlorohydrin, the hydrin rubber as the copolymer including:
 about 20% to about 29.1% epichlorohydrin by weight based on a weight of the hydrin rubber, and 
 at least one selected from the group consisting of allyl glycidyl ether and ethylene oxide, 
 
 wherein the about 20% to about 29.1% epichlorohydrin and the at least one selected from the group consisting of allyl glycidyl ether and ethylene oxide are copolymerized to have:
 a complex viscosity in the range of about 70,000 to about 100,000 Pa·s at 100° C., and 
 a Δη*/ΔT value of about 250 Pa·s/° C. or less, where
 ΔT is a temperature variation in ° C. when the temperature is changed from 60° C. to 100° C., and 
 Δη* is a complex viscosity variation (in Pa·s) when the temperature is changed from 60° C. to 100° C. at an angular frequency of 1 rad/s, 
 
 
 
 thereby to inhibit the forming of the migration pathways of the free epichlorohydrin such that an extracted amount of the free epichlorohydrin from the elastic layer is about 2% by volume or less, where:
 the extracted amount of the free epichlorohydrin is determined based on a reduced amount of chlorine (Cl) intensity measured using X-ray fluorescence (XRF) analysis performed before and after extraction of the free epichlorohydrin from the elastic layer using tetrahydrofuran (THF), and 
 the extracted amount of the free epichlorohydrin is calculated using a calibration curve, which is obtained by the XRF analysis, indicating a correlation between concentrations (in % by volume) of the free epichlorohydrin contained in a plurality of the THF solutions comprising known different concentrations of the free epichlorohydrin and the corresponding chlorine (Cl) intensities (in cps/μA) of the plurality of the THF solutions measured by the XRF analysis. 
 
 
     
     
       2. The semiconductive roller of  claim 1 , wherein the about 20% to about 29.1% epichlorohydrin and the at least one selected from the group consisting of allyl glycidyl ether and ethylene oxide are copolymerized to have the Δη*/ΔT value of about 100 Pa·s/° C. or less. 
     
     
       3. The semiconductive roller of  claim 1 , wherein the elastic layer formed of the semiconductive rubber composition has an electrical resistance of about 10 to about 300 MΩ under a condition of at 23° C. and at a relative humidity (RH) of 55%. 
     
     
       4. The semiconductive roller of  claim 1 , wherein the base rubber comprises at least one selected from the group consisting of an acrylonitrile-butadiene rubber (NBR), a styrene-butadiene rubber (SBR), a chloroprene rubber (CR), an isoprene rubber (IR), an acrylic rubber (ACM), an urethane rubber (UR), a butadiene rubber (BR), an ethylene-propylene-diene rubber (EPDM), and a silicone rubber (SiR). 
     
     
       5. The semiconductive roller of  claim 1 , wherein the base rubber is an acrylonitrile-butadiene rubber (NBR). 
     
     
       6. The semiconductive roller of  claim 1 , wherein the semiconductive rubber composition further comprises about 1 to about 30 parts by weight of an organic or inorganic filler. 
     
     
       7. The semiconductive roller of  claim 6 , wherein the filler is a nano-scale filler having an average particle diameter of about 10 nm to about 100 nm and comprises one selected from the group consisting of calcium carbonate, silica, and nano fibril cellulose (NFC). 
     
     
       8. The semiconductive roller of  claim 1 , wherein the elastic layer is a foamed layer or a solid layer. 
     
     
       9. The semiconductive roller of  claim 1 , wherein the elastic layer is formed on an outer circumferential surface of a shaft formed of an electroconductive material. 
     
     
       10. The semiconductive roller of  claim 1 , wherein the semiconductive roller is a transfer roller to transfer a toner image developed on a surface of a photoreceptor onto an image receiving member in an image-forming apparatus utilizing electrophotography. 
     
     
       11. A semiconductive roller, comprising:
 an elastic layer formed of a semiconductive rubber composition including:
 about 50 to about 70 parts by weight of a base rubber; 
 at least one nano-scale filler having an average particle diameter of about 10 to about 100 nm and selected from the group consisting of calcium carbonate, silica, and nano fibril cellulose (NFC); and 
 about 30 to about 50 parts by weight of a hydrin rubber as a copolymer inhibiting forming of migration pathways of free epichlorohydrin, the hydrin rubber as the copolymer including:
 about 20% to about 29.1% epichlorohydrin by weight based on a weight of the hydrin rubber, and 
 at least one selected from the group consisting of allyl glycidyl ether and ethylene oxide, 
 
 wherein the about 20% to about 29.1% epichlorohydrin and the at least one selected from the group consisting of allyl glycidyl ether and ethylene oxide are copolymerized to have:
 a complex viscosity in the range of about 70,000 to about 100,000 Pa·s at 100° C., and 
 a Δη*/ΔT value of about 250 Pa·s/° C. or less, where
 ΔT is a temperature variation in ° C. when the temperature is changed from 60° C. to 100° C., and 
 Δη* is a complex viscosity variation (in Pa·s) when the temperature is changed from 60° C. to 100° C. at an angular frequency of 1 rad/s, 
 
 
 
 thereby to inhibit the forming of the migration pathways of the free epichlorohydrin such that an extracted amount of the free epichlorohydrin from the elastic layer is about 2% by volume or less, where:
 the extracted amount of the free epichlorohydrin is determined based on a reduced amount of chlorine (Cl) intensity measured using X-ray fluorescence (XRF) analysis performed before and after extraction of the free epichlorohydrin from the elastic layer using tetrahydrofuran (THF), and 
 the extracted amount of the free epichlorohydrin is calculated using a calibration curve, which is obtained by the XRF analysis, indicating a correlation between concentrations (in % by volume) of the free epichlorohydrin contained in a plurality of the THF solutions comprising known different concentrations of the free epichlorohydrin and the corresponding chlorine (Cl) intensities (in cps/μA) of the plurality of the THF solutions measured by the XRF analysis.